We were expecting some reports of this after some issues around 4pm with some new code that was deployed to the service. It essentially caused a race to run on two different servers, and thus two different outcomes existed and were posted to the server after the race. It was nothing more or less severe than that, and it will not happen again now that the issue has been addressed.
We may be able to fix the results in some cases by re-running them. Please post here if this happened to you this evening and I will try to repair it. By re-importing the results sometimes it will revert to the race that you saw, and not the other one.